# Copyright (c) 2020 The Bitcoin Core developers
# Distributed under the MIT software license, see the accompanying
# file COPYING or http://www.opensource.org/licenses/mit-license.php.
"""
Test addr relay
"""

import random
import time

from test_framework.messages import (
    NODE_NETWORK,
    CAddress,
    msg_addr,
    msg_getaddr,
    msg_verack,
)
from test_framework.p2p import P2PInterface, p2p_lock
from test_framework.test_framework import BitcoinTestFramework
from test_framework.util import (
    assert_equal,
    assert_greater_than,
    assert_greater_than_or_equal,
)

ONE_MINUTE = 60
TEN_MINUTES = 10 * ONE_MINUTE
ONE_HOUR = 60 * ONE_MINUTE
TWO_HOURS = 2 * ONE_HOUR
ONE_DAY = 24 * ONE_HOUR

ADDR_DESTINATIONS_THRESHOLD = 4


class AddrReceiver(P2PInterface):
    num_ipv4_received = 0
    test_addr_contents = False
    _tokens = 1
    send_getaddr = True

    def __init__(self, test_addr_contents=False, send_getaddr=True):
        super().__init__()
        self.test_addr_contents = test_addr_contents
        self.send_getaddr = send_getaddr

    def on_addr(self, message):
        for addr in message.addrs:
            self.num_ipv4_received += 1
            if self.test_addr_contents:
                # relay_tests checks the content of the addr messages match
                # expectations based on the message creation in setup_addr_msg
                assert_equal(addr.nServices, NODE_NETWORK)
                if not 8333 <= addr.port < 8343:
                    raise AssertionError(
                        f"Invalid addr.port of {addr.port} (8333-8342 expected)"
                    )
                assert addr.ip.startswith("123.123.123.")

    def on_getaddr(self, message):
        # When the node sends us a getaddr, it increments the addr relay tokens
        # for the connection by 1000
        self._tokens += 1000

    @property
    def tokens(self):
        with p2p_lock:
            return self._tokens

    def increment_tokens(self, n):
        # When we move mocktime forward, the node increments the addr relay
        # tokens for its peers
        with p2p_lock:
            self._tokens += n

    def addr_received(self):
        return self.num_ipv4_received != 0

    def on_version(self, message):
        self.send_message(msg_verack())
        if self.send_getaddr:
            self.send_message(msg_getaddr())

    def getaddr_received(self):
        return self.message_count["getaddr"] > 0


class AddrTest(BitcoinTestFramework):
    counter = 0
    mocktime = int(time.time())

    def set_test_params(self):
        self.num_nodes = 1
        self.extra_args = [["-whitelist=addr@127.0.0.1"]]

    def run_test(self):
        self.oversized_addr_test()
        self.relay_tests()
        self.inbound_blackhole_tests()

        self.destination_rotates_once_in_24_hours_test()
        self.destination_rotates_more_than_once_over_several_days_test()

        # This test populates the addrman, which can impact the node's behavior
        # in subsequent tests
        self.getaddr_tests()
        self.blocksonly_mode_tests()
        self.rate_limit_tests()

    def setup_addr_msg(self, num):
        addrs = []
        for i in range(num):
            addr = CAddress()
            addr.time = self.mocktime + i
            addr.nServices = NODE_NETWORK
            addr.ip = f"123.123.123.{self.counter % 256}"
            addr.port = 8333 + i
            addrs.append(addr)
            self.counter += 1

        msg = msg_addr()
        msg.addrs = addrs
        return msg

    def setup_rand_addr_msg(self, num):
        addrs = []
        for i in range(num):
            addr = CAddress()
            addr.time = self.mocktime + i
            addr.nServices = NODE_NETWORK
            addr.ip = (
                f"{random.randrange(128, 169)}.{random.randrange(1, 255)}"
                f".{random.randrange(1, 255)}.{random.randrange(1, 255)}"
            )
            addr.port = 8333
            addrs.append(addr)
        msg = msg_addr()
        msg.addrs = addrs
        return msg

    def send_addr_msg(self, source, msg, receivers):
        source.send_and_ping(msg)
        # pop m_next_addr_send timer
        self.mocktime += 10 * 60
        self.nodes[0].setmocktime(self.mocktime)
        for peer in receivers:
            peer.sync_with_ping()

    def oversized_addr_test(self):
        self.log.info("Send an addr message that is too large")
        addr_source = self.nodes[0].add_p2p_connection(P2PInterface())

        msg = self.setup_addr_msg(1010)
        with self.nodes[0].assert_debug_log(["addr message size = 1010"]):
            addr_source.send_message(msg)
            addr_source.wait_for_disconnect()

        self.nodes[0].disconnect_p2ps()

    def relay_tests(self):
        self.log.info("Test address relay")
        self.log.info("Check that addr message content is relayed and added to addrman")
        addr_source = self.nodes[0].add_p2p_connection(P2PInterface())
        num_receivers = 7
        receivers = []
        for _ in range(num_receivers):
            receivers.append(
                self.nodes[0].add_p2p_connection(AddrReceiver(test_addr_contents=True))
            )

        # Keep this with length <= 10. Addresses from larger messages are not
        # relayed.
        num_ipv4_addrs = 10
        msg = self.setup_addr_msg(num_ipv4_addrs)
        with self.nodes[0].assert_debug_log(
            [
                "received: addr (301 bytes) peer=1",
            ]
        ):
            self.send_addr_msg(addr_source, msg, receivers)

        total_ipv4_received = sum(r.num_ipv4_received for r in receivers)

        # Every IPv4 address must be relayed to two peers, other than the
        # originating node (addr_source).
        ipv4_branching_factor = 2
        assert_equal(total_ipv4_received, num_ipv4_addrs * ipv4_branching_factor)

        self.nodes[0].disconnect_p2ps()

        self.log.info("Check relay of addresses received from outbound peers")
        inbound_peer = self.nodes[0].add_p2p_connection(
            AddrReceiver(test_addr_contents=True, send_getaddr=False)
        )
        full_outbound_peer = self.nodes[0].add_outbound_p2p_connection(
            AddrReceiver(), p2p_idx=0, connection_type="outbound-full-relay"
        )
        msg = self.setup_addr_msg(2)
        self.send_addr_msg(full_outbound_peer, msg, [inbound_peer])
        self.log.info(
            "Check that the first addr message received from an outbound peer is not"
            " relayed"
        )
        # Currently, there is a flag that prevents the first addr message
        # received from a new outbound peer to be relayed to others. Originally
        # meant to prevent large GETADDR responses from being relayed, it now
        # typically affects the self-announcement of the outbound peer which is
        # often sent before the GETADDR response.
        assert_equal(inbound_peer.num_ipv4_received, 0)

        # Send an empty ADDR message to initialize address relay on this
        # connection.
        inbound_peer.send_and_ping(msg_addr())

        self.log.info(
            "Check that subsequent addr messages sent from an outbound peer are relayed"
        )
        msg2 = self.setup_addr_msg(2)
        self.send_addr_msg(full_outbound_peer, msg2, [inbound_peer])
        assert_equal(inbound_peer.num_ipv4_received, 2)

        self.log.info("Check address relay to outbound peers")
        block_relay_peer = self.nodes[0].add_outbound_p2p_connection(
            AddrReceiver(), p2p_idx=1, connection_type="block-relay-only"
        )
        msg3 = self.setup_addr_msg(2)
        self.send_addr_msg(inbound_peer, msg3, [full_outbound_peer, block_relay_peer])

        self.log.info("Check that addresses are relayed to full outbound peers")
        assert_equal(full_outbound_peer.num_ipv4_received, 2)
        self.log.info(
            "Check that addresses are not relayed to block-relay-only outbound peers"
        )
        assert_equal(block_relay_peer.num_ipv4_received, 0)

        self.nodes[0].disconnect_p2ps()

    def sum_addr_messages(self, msgs_dict):
        return sum(
            bytes_received
            for (msg, bytes_received) in msgs_dict.items()
            if msg in ["addr", "addrv2", "getaddr"]
        )

    def inbound_blackhole_tests(self):
        self.log.info(
            "Check that we only relay addresses to inbound peers who have previously"
            " sent us addr related messages"
        )

        addr_source = self.nodes[0].add_p2p_connection(P2PInterface())
        receiver_peer = self.nodes[0].add_p2p_connection(AddrReceiver())
        blackhole_peer = self.nodes[0].add_p2p_connection(
            AddrReceiver(send_getaddr=False)
        )
        initial_addrs_received = receiver_peer.num_ipv4_received

        peerinfo = self.nodes[0].getpeerinfo()
        assert_equal(peerinfo[0]["addr_relay_enabled"], True)  # addr_source
        assert_equal(peerinfo[1]["addr_relay_enabled"], True)  # receiver_peer
        assert_equal(peerinfo[2]["addr_relay_enabled"], False)  # blackhole_peer

        # addr_source sends 2 addresses to node0
        msg = self.setup_addr_msg(2)
        addr_source.send_and_ping(msg)
        self.mocktime += 30 * 60
        self.nodes[0].setmocktime(self.mocktime)
        receiver_peer.sync_with_ping()
        blackhole_peer.sync_with_ping()

        peerinfo = self.nodes[0].getpeerinfo()

        # Confirm node received addr-related messages from receiver peer
        assert_greater_than(self.sum_addr_messages(peerinfo[1]["bytesrecv_per_msg"]), 0)
        # And that peer received addresses
        assert_equal(receiver_peer.num_ipv4_received - initial_addrs_received, 2)

        # Confirm node has not received addr-related messages from blackhole
        # peer
        assert_equal(self.sum_addr_messages(peerinfo[2]["bytesrecv_per_msg"]), 0)
        # And that peer did not receive addresses
        assert_equal(blackhole_peer.num_ipv4_received, 0)

        self.log.info(
            "After blackhole peer sends addr message, it becomes eligible for addr"
            " gossip"
        )
        blackhole_peer.send_and_ping(msg_addr())

        # Confirm node has now received addr-related messages from blackhole
        # peer
        assert_greater_than(self.sum_addr_messages(peerinfo[1]["bytesrecv_per_msg"]), 0)
        assert_equal(self.nodes[0].getpeerinfo()[2]["addr_relay_enabled"], True)

        msg = self.setup_addr_msg(2)
        self.send_addr_msg(addr_source, msg, [receiver_peer, blackhole_peer])

        # And that peer received addresses
        assert_equal(blackhole_peer.num_ipv4_received, 2)

        self.nodes[0].disconnect_p2ps()

    def getaddr_tests(self):
        # In the previous tests, the node answered GETADDR requests with an
        # empty addrman. Due to GETADDR response caching (see
        # CConnman::GetAddresses), the node would continue to provide 0 addrs
        # in response until enough time has passed or the node is restarted.
        self.restart_node(0)

        self.log.info("Test getaddr behavior")
        self.log.info(
            "Check that we send a getaddr message upon connecting to an"
            " outbound-full-relay peer"
        )
        full_outbound_peer = self.nodes[0].add_outbound_p2p_connection(
            AddrReceiver(), p2p_idx=0, connection_type="outbound-full-relay"
        )
        full_outbound_peer.sync_with_ping()
        assert full_outbound_peer.getaddr_received()

        self.log.info(
            "Check that we do not send a getaddr message upon connecting to a"
            " block-relay-only peer"
        )
        block_relay_peer = self.nodes[0].add_outbound_p2p_connection(
            AddrReceiver(), p2p_idx=1, connection_type="block-relay-only"
        )
        block_relay_peer.sync_with_ping()
        assert_equal(block_relay_peer.getaddr_received(), False)

        self.log.info("Check that we answer getaddr messages only from inbound peers")
        inbound_peer = self.nodes[0].add_p2p_connection(
            AddrReceiver(send_getaddr=False)
        )
        inbound_peer.sync_with_ping()

        # Add some addresses to addrman
        for i in range(1000):
            first_octet = i >> 8
            second_octet = i % 256
            a = f"{first_octet}.{second_octet}.1.1"
            self.nodes[0].addpeeraddress(a, 8333)

        full_outbound_peer.send_and_ping(msg_getaddr())
        block_relay_peer.send_and_ping(msg_getaddr())
        inbound_peer.send_and_ping(msg_getaddr())

        self.mocktime += 5 * 60
        self.nodes[0].setmocktime(self.mocktime)
        inbound_peer.wait_until(lambda: inbound_peer.addr_received() is True)

        assert_equal(full_outbound_peer.num_ipv4_received, 0)
        assert_equal(block_relay_peer.num_ipv4_received, 0)
        assert inbound_peer.num_ipv4_received > 100

        self.nodes[0].disconnect_p2ps()

    def blocksonly_mode_tests(self):
        self.log.info("Test addr relay in -blocksonly mode")
        self.restart_node(0, ["-blocksonly", "-whitelist=addr@127.0.0.1"])
        self.mocktime = int(time.time())

        self.log.info("Check that we send getaddr messages")
        full_outbound_peer = self.nodes[0].add_outbound_p2p_connection(
            AddrReceiver(), p2p_idx=0, connection_type="outbound-full-relay"
        )
        full_outbound_peer.sync_with_ping()
        assert full_outbound_peer.getaddr_received()

        self.log.info("Check that we relay address messages")
        addr_source = self.nodes[0].add_p2p_connection(P2PInterface())
        msg = self.setup_addr_msg(2)
        self.send_addr_msg(addr_source, msg, [full_outbound_peer])
        assert_equal(full_outbound_peer.num_ipv4_received, 2)

        self.nodes[0].disconnect_p2ps()

    def send_addrs_and_test_rate_limiting(
        self, peer, no_relay, *, new_addrs, total_addrs
    ):
        """Send an addr message and check that the number of addresses processed
        and rate-limited is as expected
        """
        peer.send_and_ping(self.setup_rand_addr_msg(new_addrs))

        peerinfo = self.nodes[0].getpeerinfo()[0]
        addrs_processed = peerinfo["addr_processed"]
        addrs_rate_limited = peerinfo["addr_rate_limited"]
        self.log.debug(
            f"addrs_processed = {addrs_processed}, "
            f"addrs_rate_limited = {addrs_rate_limited}"
        )

        if no_relay:
            assert_equal(addrs_processed, 0)
            assert_equal(addrs_rate_limited, 0)
        else:
            assert_equal(addrs_processed, min(total_addrs, peer.tokens))
            assert_equal(addrs_rate_limited, max(0, total_addrs - peer.tokens))

    def rate_limit_tests(self):
        self.mocktime = int(time.time())
        self.restart_node(0, [])
        self.nodes[0].setmocktime(self.mocktime)

        for conn_type, no_relay in [
            ("outbound-full-relay", False),
            ("block-relay-only", True),
            ("inbound", False),
        ]:
            self.log.info(
                f"Test rate limiting of addr processing for {conn_type} peers"
            )
            if conn_type == "inbound":
                peer = self.nodes[0].add_p2p_connection(AddrReceiver())
            else:
                peer = self.nodes[0].add_outbound_p2p_connection(
                    AddrReceiver(), p2p_idx=0, connection_type=conn_type
                )

            # Send 600 addresses. For all but the block-relay-only peer this
            # should result in addresses being processed.
            self.send_addrs_and_test_rate_limiting(
                peer, no_relay, new_addrs=600, total_addrs=600
            )

            # Send 600 more addresses. For the outbound-full-relay peer (which
            # we send a GETADDR, and thus will process up to 1001 incoming
            # addresses), this means more addresses will be processed.
            self.send_addrs_and_test_rate_limiting(
                peer, no_relay, new_addrs=600, total_addrs=1200
            )

            # Send 10 more. As we reached the processing limit for all nodes,
            # no more addresses should be procesesd.
            self.send_addrs_and_test_rate_limiting(
                peer, no_relay, new_addrs=10, total_addrs=1210
            )

            # Advance the time by 100 seconds, permitting the processing of 10
            # more addresses.
            # Send 200 and verify that 10 are processed.
            self.mocktime += 100
            self.nodes[0].setmocktime(self.mocktime)
            peer.increment_tokens(10)

            self.send_addrs_and_test_rate_limiting(
                peer, no_relay, new_addrs=200, total_addrs=1410
            )

            # Advance the time by 1000 seconds, permitting the processing of 100
            # more addresses.
            # Send 200 and verify that 100 are processed.
            self.mocktime += 1000
            self.nodes[0].setmocktime(self.mocktime)
            peer.increment_tokens(100)

            self.send_addrs_and_test_rate_limiting(
                peer, no_relay, new_addrs=200, total_addrs=1610
            )

            self.nodes[0].disconnect_p2ps()

    def get_nodes_that_received_addr(
        self, peer, receiver_peer, addr_receivers, time_interval_1, time_interval_2
    ):
        # Clean addr response related to the initial getaddr. There is no way to avoid initial
        # getaddr because the peer won't self-announce then.
        for addr_receiver in addr_receivers:
            addr_receiver.num_ipv4_received = 0

        for _ in range(10):
            self.mocktime += time_interval_1
            self.msg.addrs[0].time = self.mocktime + TEN_MINUTES
            self.nodes[0].setmocktime(self.mocktime)
            with self.nodes[0].assert_debug_log(["received: addr (31 bytes) peer=0"]):
                peer.send_and_ping(self.msg)
                self.mocktime += time_interval_2
                self.nodes[0].setmocktime(self.mocktime)
                receiver_peer.sync_with_ping()
        return [node for node in addr_receivers if node.addr_received()]

    def destination_rotates_once_in_24_hours_test(self):
        self.restart_node(0, [])

        self.log.info(
            "Test within 24 hours an addr relay destination is rotated at most once"
        )
        self.mocktime = int(time.time())
        self.msg = self.setup_addr_msg(1)
        self.addr_receivers = []
        peer = self.nodes[0].add_p2p_connection(P2PInterface())
        receiver_peer = self.nodes[0].add_p2p_connection(AddrReceiver())
        addr_receivers = [
            self.nodes[0].add_p2p_connection(AddrReceiver()) for _ in range(20)
        ]
        nodes_received_addr = self.get_nodes_that_received_addr(
            peer, receiver_peer, addr_receivers, 0, TWO_HOURS
        )  # 10 intervals of 2 hours
        # Per RelayAddress, we would announce these addrs to 2 destinations per day.
        # Since it's at most one rotation, at most 4 nodes can receive ADDR.
        assert_greater_than_or_equal(
            ADDR_DESTINATIONS_THRESHOLD, len(nodes_received_addr)
        )
        self.nodes[0].disconnect_p2ps()

    def destination_rotates_more_than_once_over_several_days_test(self):
        self.restart_node(0, [])

        self.log.info(
            "Test after several days an addr relay destination is rotated more than once"
        )
        self.msg = self.setup_addr_msg(1)
        peer = self.nodes[0].add_p2p_connection(P2PInterface())
        receiver_peer = self.nodes[0].add_p2p_connection(AddrReceiver())
        addr_receivers = [
            self.nodes[0].add_p2p_connection(AddrReceiver()) for _ in range(20)
        ]
        # 10 intervals of 1 day (+ 1 hour, which should be enough to cover 30-min Poisson in most cases)
        nodes_received_addr = self.get_nodes_that_received_addr(
            peer, receiver_peer, addr_receivers, ONE_DAY, ONE_HOUR
        )
        # Now that there should have been more than one rotation, more than
        # ADDR_DESTINATIONS_THRESHOLD nodes should have received ADDR.
        assert_greater_than(len(nodes_received_addr), ADDR_DESTINATIONS_THRESHOLD)
        self.nodes[0].disconnect_p2ps()


if __name__ == "__main__":
    AddrTest().main()
